validateMimeTypes function
Returns extensions whose value here equals package:mime's default —
pure duplicates, safe to delete. Intentional overrides (where our
value differs from the SDK) are excluded. For debugging only.
Implementation
List<String> validateMimeTypes() {
final duplicates = <String>[];
for (final entry in _mimeMap.entries)
if (lookupMimeType(".${entry.key}") == entry.value)
duplicates.add(entry.key);
return duplicates;
}